JPH11157058A - Printer driver, image forming device, and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of the quality level of a recorded image even when the temperature of a plurality of recording heads is fluctuated. SOLUTION: The temperature of a plurality of recording heads is measured (S2), and based on one measured recording temperature, the target temperature of the other recording head is so set (S5, S6) as to keep the given density relationship between one recording head and the other recording head (S3, S4), and the temperature of the other recording head is adjusted to comply with the set target temperature, and an image is formed by using a plurality of recording heads.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for recording characters, images, and the like on a recording medium while relatively scanning a plurality of recording heads facing the recording medium. In particular, the present invention is suitable for a shuttle type recording apparatus in which a plurality of recording heads arranged at predetermined intervals can perform recording while scanning corresponding divided recording areas.

Further, the present invention is suitable for a recording apparatus that performs recording by applying a color material on a recording medium based on image data, and performs recording by discharging a liquid recording ink as the color material. This is more suitable for an ink jet recording apparatus.

Further, the present invention relates to paper, cloth, leather, nonwoven fabric, O
The present invention is applicable to all devices that use a recording medium such as HP paper or metal. Specific examples of these applicable equipment include office equipment such as printers, copiers, and facsimile machines, and industrial production equipment.

[0004]

2. Description of the Related Art A serial type recording system in which recording is performed while scanning a recording head is inexpensive as compared with a system using a full line head which covers the entire width of a recording medium such as recording paper. It is generally used in various recording devices. On the other hand, full line heads are used in printing apparatuses that require high-speed printing.
Among the recording apparatuses, those that cause a heating element of a thermal head to act on a special heat-sensitive paper or that optically record and develop a color on a special photosensitive paper are known as coloring apparatuses for coloring a recording medium. . Various systems have been put into practical use or proposed as systems for performing recording by applying a color material to a recording medium using a recording head. For example, an ink ribbon impregnated with a liquid ink as a color material is pressed against a recording medium by a print wire, and the ink is transferred by contacting the ink ribbon with an ink ribbon head coated with a solid color material. There are a thermal melting transfer recording method or a thermal sublimation transfer method in which ink is transferred by causing a heating element of a thermal head to act, and an ink jet method in which a liquid recording ink is discharged to perform recording.

[0005] In recent years, from the viewpoint of plain paper recording, the latter colorant-applied recording system has become mainstream. In particular, the ink jet recording method has advantages such as low noise, low running cost, easy downsizing of the apparatus, recording on plain paper, and easy colorization, and is generally used for recording apparatuses such as printers and copiers. It is used regularly.

[0006] Some of such printing apparatuses are equipped with a plurality of print heads to realize color printing, gradation printing, and high-resolution printing. For example, Y (yellow),
Color printing can be realized by mounting a head of four colors of M (magenta), C (cyan), and K (black) or a head of three colors of Y, M, and C. By mounting a dark head capable of recording at high density and a light head capable of recording at low density, gradation recording can be realized. By mounting a plurality of heads of the same color in an interlaced state, high-resolution recording can be realized.

[0007] Among the printing apparatuses, the serial printing method is such that a printing head capable of printing only in a relatively small area with a limited printing element, such as an ejection port provided in the printing head, is provided on a carriage and sequentially scanned. It is relatively difficult to improve the recording speed because the recording is performed while
High-speed recording has been a conventional problem for the serial system.

One relatively effective method for increasing the speed of a serial type image recording apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 50-81437.
No. 4,272,771. This publication uses a left print head assembly and a right print head assembly supported by one carriage mechanism to simultaneously print the left half and the right half of a print line, thereby increasing the speed by about twice. Can be realized. Further, the publication discloses that a higher recording speed can be realized by increasing the number of print head assemblies to two or more or by performing bidirectional recording.

As described above, a plurality of heads have been cooperated or shared to achieve color recording, high image quality, and high speed recording. At this time, it is necessary to maintain a predetermined density relationship between the plurality of heads. If this relationship is lost, the quality of the recorded image will be degraded, for example, the color balance will be lost, the gray balance will be lost, and the density will be uneven.

For example, in a configuration in which a plurality of recording heads are shared in the scanning direction and recording is performed on a paper surface, each recording head may have different characteristics due to differences in the characteristics of the heads or differences in the characteristics of recording materials such as ink and ink ribbon. A density difference occurs between recording areas where the head records.

FIGS. 1A and 1B show the phenomenon. Here, two heads, head A and head B, are used, and a case is shown in which head B has a relatively high density output characteristic than head A.
(A) shown in FIG. 1 is 25%, 5% when the recording area of the head A and the recording area of the head B are completely divided into two at the center of the sheet.
It shows the recording results for three levels of print duty of 0% and 100%. As is clear from the figure,
Regardless of the duty, the density difference between the two can be clearly confirmed at the boundary.

FIG. 1B shows a similar recording result in the case where some overlapping areas are provided in the recording areas of the head A and the head B. In the overlapping recording area, the two heads thin out almost half the data, and the two recordings overlap each other to complete the image complementarily.
Therefore, the density of the entire overlapping recording area is higher than the recording area of the head A only, and lower than the recording area of the head B only. In this case, although a clear density difference as shown in FIG. 1A does not appear, the density difference between the regions on both sides of the overlapping region becomes clear. As described above, it is necessary to correct a density difference caused by a difference in output characteristics between the two heads.

Therefore, it is conceivable to select heads having the same characteristics and use them, but this is not practical in a printer of a head (head cartridge) exchange type. For this reason, the density between the plurality of heads is adjusted to have a predetermined relationship by means for correcting the density of the heads. For example, the image signal is corrected, the drive signal is corrected, and the temperature of the head is adjusted.

[0014]

However, since the recording signals (image data) supplied to the plurality of heads are different, the duty of the recording signals is also different. Therefore, the driving duty of the head is different, and the temperature of the head is also different. As is well known, the recording density of the head has a temperature characteristic, and therefore, when the temperature of the head fluctuates, a predetermined density relationship cannot be maintained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printer driver, an image forming apparatus, and a method of controlling the same, which can prevent deterioration of the quality of a printed image even when the temperatures of a plurality of print heads fluctuate.

Another object of the present invention is to provide a printer driver, an image forming apparatus, and a method of controlling the same that allow a plurality of print heads to maintain a predetermined density relationship even when the temperatures of the plurality of print heads fluctuate. Aim.

Still another object of the present invention is to provide a printer driver, an image forming apparatus, and a control method for the same that do not cause density unevenness even when the temperatures of a plurality of recording heads fluctuate.

Another object of the present invention is to provide a printer driver, an image forming apparatus, and a control method thereof, in which the color balance does not fluctuate even when the temperatures of a plurality of recording heads fluctuate.

It is a further object of the present invention to provide a printer driver, an image forming apparatus, and a control method thereof, in which the gray balance does not change even when the temperatures of a plurality of recording heads change.

It is a further object of the present invention to provide a printer driver, an image forming apparatus, and a control method thereof, in which the gradation balance does not fluctuate even when the temperatures of a plurality of recording heads fluctuate.

[0021]

In order to achieve the above object, the present invention provides a method for controlling an image forming apparatus for forming an image using a plurality of recording heads, the method comprising: acquiring temperatures of a plurality of recording heads; Based on the acquired temperature of one of the printheads, an image formed by the one printhead and the other printhead maintains a predetermined density relationship,
A target temperature of the other printhead is set, the temperature of the other printhead is adjusted to the set target temperature, and an image is formed using the plurality of printheads.

According to another aspect of the present invention, there is provided an image forming apparatus for forming an image using a plurality of recording heads, comprising: an acquiring unit for acquiring a temperature of the plurality of recording heads; Based on the recording head temperature,
Setting means for setting a target temperature of the other recording head so that an image formed by the one recording head and the other recording head maintains a predetermined density relationship; and Adjusting means for adjusting the temperature of the recording head.

According to another aspect of the present invention, there is provided a printer driver installed in a host computer for controlling a printer, comprising: a code for acquiring temperatures of a plurality of recording heads mounted on the printer; The target temperature of the other recording head is controlled by the printer so that an image formed by the one recording head and the other recording head maintains a predetermined density relationship based on the acquired temperature of the one recording head. And a code for setting

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 2 is a diagram for explaining divided printing and overlapping printing in a printing apparatus using two print heads. In FIG. 2, the carriage 1 is provided with 72 ink jet recording heads 4A and 4B.
The tanks 5A and 5B, which are mounted with a head interval of mm and store ink supplied to each head, are mounted. The head and the tank are configured to be detachable from the carriage 1 individually.
Note that, depending on the type of ink used as described below, the head and the tank may be formed integrally, and the integrated head and tank may be made detachable from the carriage 1.

The carriage 1 is slidably supported by a guide rail 2 and engages with a drive mechanism (not shown) such as a belt for transmitting a driving force of drive data (not shown). 2 for scanning along. As a result, the carriage 1 can be moved within the scannable space (358 mm) shown in FIG. At this time, the respective ink ejection ports of the heads 4A and 4B can be located in the respective scanning areas (258 mm). The head 4A scans a divided recording area (226 mm), which is a divided scanning area on the left side of the drawing, except for a ramp-up and a ramp-down area, which are acceleration / deceleration areas during carriage movement. On the other hand, the head 4B has a divided recording area (226 m
m) will be scanned.

A part of the carriage 1 in the scannable space, that is, below the extending platen 3, two heads 4A
And caps 6A and 6B corresponding to the ink ejection ports of 4B and 4B.
B is provided. Thus, capping of each head can be performed at the home position. Further, a pump 7 for sucking ink or the like is connected to the cap 6B provided in the recording area through the cap 6B. When each head 4A and 4B is moved to a position facing the cap 6B at a predetermined timing, and the cap 6B is moved in the head direction in the same manner as the capping operation, the suction operation by the pump 7 is performed in this state. It can be carried out. Further, a wiper 8 is provided adjacent to the cap 6B, and the wiper 8 projects at a predetermined timing into the scanning path of the head, so that the wiper 8 comes into contact with the ejection opening surface of each head and wiping can be performed. .

Further, in the scannable space of the carriage 1, a preliminary ejection receiver 9 is provided at an end opposite to the end where the cap 6A is provided, and the head 4B is moved to this position at a predetermined timing. To perform a preliminary ejection. The preliminary ejection of the head 4A is performed by the head 4B.
Similarly to the case described above, it becomes possible by moving the head 4A to a position facing the cap 6A. As mentioned above,
By providing a configuration for suction recovery in the recording area and also as a dual-purpose configuration, or by providing a preliminary discharge receiver at the end opposite to each other for each head, the maximum recordable area in the scannable space of the carriage , In other words, the size of the apparatus can be made as small as possible for a certain maximum recordable area.

In the printing apparatus of the present embodiment described above, the head interval (72 mm), which is the distance between the ejection ports of the heads 4A and 4B, is the maximum printable area that can be achieved by sharing the scanning area of each head. (298m
m) is set to approximately 1/4. Then, the width of the overlapping scanning area is 154 mm. These size settings are for A3 (297 m
The width corresponds to the width of a sheet (recording medium) of a standard size of mx 420 mm), while the overlapping scanning area is A5 (148).
It corresponds to the width of a paper of a standard size (mm × 210 mm). That is, the width of the maximum recordable area is set to approximately twice the width of the overlap scanning area.

In this embodiment, when printing is performed on, for example, A3 size paper corresponding to the maximum printable area, the same type of ink is ejected from the heads 4A and 4B, respectively, and each divided print area is shared. Make a record. On the other hand, when printing is performed on, for example, A5 size paper corresponding to the overlapping recording area, one of the heads, for example, the head 4B is replaced with a head that discharges light ink, and the dark and light inks having different densities are used. Records can be made in cooperation.

According to the recording apparatus of the present embodiment shown in FIG. 2, when recording in the A3 size, recording can be performed by sharing the maximum recordable area using two heads. As a result, the recording speed can be improved. At the same time, by maximizing the maximum recordable area with respect to the carriage scannable space, the size of the recording apparatus can be reduced.

Even in the case of monochrome recording such as black and white, the configuration of the present embodiment provides a great effect. When color recording is performed using a plurality of ink colors, the effect can be more clearly understood in terms of the ink storage volume of the ink tank. Therefore, in the present embodiment, an example is described in which four color inks of black (Bk), cyan (C), magenta (M), and yellow (Y) are used, and all the color ink tanks can be replaced independently. . That is, B is provided on both sides of the carriage 1.
Recording heads 4A and 4B integrally provided with ejection port groups for each ink color for ejecting k, C, M and Y respectively, and a central part Bk for supplying ink common to both of these recording heads
Tank, C tank, M tank, and Y tank are mounted. In this embodiment, ink is supplied to the two recording heads from the same ink tank as described above. However, the present invention is not limited to this. For example, one ink tank is mounted for each head, and they may be integrated with each head, or the tank may be removable from the head.

FIG. 3 is a block diagram showing the configuration of the heating element driving section of the recording head 4 (4A, 4B). Heating element 41
-1 to 41-160 are provided corresponding to all the ink ejection ports, respectively, and have a configuration capable of independently generating heat. Here, 160 corresponds to the sum of 24 for Y (yellow), M (magenta), and C (cyan), 64 for K (black), and 8 for each color. Heating element 4
When all 1s are driven at the same time, a large current flows at a time, and the load on the power supply increases. In addition, since the energy supplied to each heating element decreases due to a voltage drop such as wiring resistance, there is a possibility that normal recording may not be performed.
As described above, there is a concern about the adverse effect on the image quality. Therefore,
In the head according to the present embodiment, the recording head 4 is arranged at a slight inclination, and a known time-division driving is performed in which ejection is performed by adjusting image data and recording timing for each block including a predetermined number of heating elements.

As the time division driving method, any of various methods proposed and implemented may be adopted. In the present embodiment, eight blocks are divided into 20 blocks each including eight ports, which are intervals between ink colors, and the blocks are sequentially discharged at predetermined intervals.
Correspondingly, the recording head 4 is tilted to perform ejection in accordance with the scanning speed of the recording head 4, thereby preventing a linearly inclined recording due to the ejection time difference.

The ink in the discharge port, which is rapidly heated by the heat generated by the heating element 41, forms bubbles due to film boiling. Due to the pressure of the bubble generation, ink droplets are ejected toward the recording medium P, and characters and images are formed on the recording medium.
At this time, the volume of each color ink droplet ejected is about 40 ng.
It is. Each of the discharge ports communicates with the discharge port and has a heating element 4.
1 are provided, and a common liquid chamber for supplying ink to these liquid paths is provided for each color behind a portion where the ink liquid paths are provided.

Inks are supplied from the common liquid chamber to the ink tanks 5 (5A, 5B) of the respective colors via ink supply paths.
The ink path corresponding to each of the discharge ports has electricity / electricity for generating thermal energy used for discharging ink droplets.
A heating element 41, which is a heat conversion element, and electrode wiring for supplying power to the heating element 41 are provided. These heating elements 41 and electrode wirings are formed on a substrate made of silicon or the like by a film forming technique. On the heating element 41, the ink and the heating element 4
A protective film is formed so that the contact members 1 do not directly contact each other. Further, the above-mentioned discharge port, ink liquid path, common liquid chamber, and the like are formed by laminating a partition made of resin or glass material on the substrate. As described above, the recording method using the heating element 41, which is an electric-to-heat converter, uses a bubble formed by applying thermal energy at the time of ejecting an ink droplet, and is therefore generally called a bubble jet recording method. .

The AND gates 42-1 to 42-160 are
The logical product of the selection signal for time division output from the decoder 43, the driving data output from the latch circuit 44, and the heat enable signal (HeatENB) for specifying the driving time is obtained, and the driving signal is sent to the heating element 41. Is output. The shift register 45 converts the serially input image data into parallel data and outputs the image data to the latch circuit 44.

As a monitoring mechanism of the recording heads 4A and 4B,
In this embodiment, the recording head 4 is further provided with a temperature sensor 46. This stabilizes the recording characteristics by determining the optimum driving conditions of the recording heads according to the temperatures of the recording heads 4A and 4B, and operating the maintenance mechanism based on the temperature information. Further, a temperature control heater 47 is provided to keep the temperature of the recording head 4 at a set temperature.

FIG. 4A is a diagram showing a system including a recording device and a host computer as a host device. The host computer is configured to perform various data processing between an OS (Operating System) 101 and application software 102 running thereon. Here, a description will be given of a data flow in a case where image data created using the application software 102 that handles pictorial images is output to a recording device via the printer driver 103 and printed out.

If the image data processed by the application software 102 is a pictorial image, a multi-valued RG
The data is sent to the printer driver 103 as B data. On the other hand, the printer driver 103 performs color processing on the multi-valued RGB data received from the application software 102, further performs halftone processing, and usually performs binary C
Convert to MYK data. The image data thus converted is output via an interface for a printer in the host computer or an interface to a storage device such as a file. In the example of FIG. 4A, image data is output via an interface to the printing apparatus.

On the other hand, the printing apparatus receives image data from the host under the control of the controller software 104, checks the print mode and the consistency of the print head 106, and then passes the received image data to the engine software 105. . The engine software 105 receives the image data as the print mode or data structure specified by the controller software 104, generates an ink ejection pulse based on the image data, and outputs the pulse to the recording head. Thus, the recording head 106 ejects the corresponding color ink to record a color image on the recording medium.

FIG. 4B is a block diagram showing a control configuration of the printing apparatus shown in FIG. 4A. From the host computer,
Character or image data to be recorded (hereinafter, referred to as image data) is input to a reception buffer of the recording device. Data for confirming that the data is correctly transferred and data for informing the operation state of the recording apparatus are transmitted from the recording apparatus to the host computer. The data in the receive buffer is
1 is controlled under the control of a print buffer (RAM) 2
After being temporarily stored in the print head 4, the print data is given to the print heads 4A and 4B as print data.

The paper feed mechanism 26 drives a paper feed roller and a line feed roller by controlling a drive source such as a motor in accordance with a command from the CPU 21 based on information of the paper monitoring mechanism 25. The carriage drive mechanism 28 includes:
CPU 21 based on information of carriage position detecting mechanism 27
By controlling the carriage drive source in accordance with the instruction from the controller, the drive by the carriage 1 is controlled. The printhead maintenance mechanism 30 is configured to control the CPU 2 based on information of the printhead monitoring mechanism 29 including a sensor such as the presence or absence of ink.
The maintenance of the head 4 and the optimization of the driving conditions can be performed according to the instruction from the controller 1.

The photo sensor 31 causes the LED 32 to emit light in accordance with an instruction from the CPU 21, and the reflected light of the test pattern formed on the paper is detected by the photodiode 33. The CPU 21 controls the temperature of the head heater 47 based on the temperature of each head detected by the temperature sensor 46, thereby controlling the temperature of the head described later in detail.

In this embodiment, recording is performed by using the two recording heads 4A and 4B shown in FIG. Here, since the recording data supplied to the heads 4A and 4B differ depending on the image, the temperature of the heads 4A and 4B may differ. When the temperature of the head increases, the viscosity of the ink decreases, so that the amount of ejected ink increases and the image density increases. FIG. 5 is a graph showing the density deviation of the plurality of heads shown in FIG. 1 and its correction.

In FIG. 5A, the density of the head 4A indicated by a solid line and the density of the head 4B indicated by a dashed line are set to be equal by known density correction means, for example, a pulse signal correction means or a head temperature correction means. (B) shown in FIG.
Indicates that the duty of the print data of the head 4A is high, and the density of the head 4A (shown by a thick solid line) is higher than the density of the head 4B. If printing is performed in this state, as described above, density unevenness occurs on the left and right sides of the printing area.

Therefore, as shown in FIG. 5C, it is necessary to increase the density of the head 4B as shown by the thick dashed line to make it equal to the density of the head 4A. Next, correction of the head density in the present embodiment will be described with reference to FIG.

(A) and (B) of FIG. 6 show that the density of the heads 4A and 4B is made equal by the head temperature correcting means.
(OD = Optical Density)
The case where the temperature of A is set to X and the temperature of head B is set to W is shown. Here, it is assumed that the temperature of the head 4A rises by V and becomes Y because the duty of the recording data to the head 4A is high. For this reason, the head 4
The recording density of A increases from O to Q.

Again, in order to make the density of the head 4B equal to the density of the head 4A, even if the temperature of the head 4B is increased by the temperature increase V of the head 4A to obtain Z, both heads 4B
The concentrations of A and 4B are not equal. That is, as shown in FIG. 6A, since the temperature-density characteristics of the heads 4A and 4B are different, even if the temperature of the head 4B is increased by V to Z, the density of the head 4B is only P. As described above, simply maintaining the relationship between the two temperatures in the predetermined relationship cannot make the densities of a plurality of recording heads having different density characteristics uniform.

In this embodiment, as shown in FIG. 6B, based on the temperature of one head (head 4A), one head and the other head (head 4B) maintain the same density. , The temperature of the other head is set.
That is, the temperature of the head 4B is set to a temperature Z 'at which the density of the head 4B becomes equal to the density Q when the temperature of the head 4A rises to V and becomes Y. At this time, the temperature of the head 4B rises not by V but by V '.

In order to perform the above-described control, in the present embodiment, a target temperature table for a predetermined density of the heads 4A and 4B having the density characteristics as shown in FIG. RAM 22 or RO for control
It is created in M23. This table contains the concentrations O, P,
Target temperatures AO, AP, AQ, AR,..., AZ, BO, BP, B of the heads 4A, 4B for obtaining Q, R,.
Q, BR,..., BZ are shown.

The control of the printer main body according to the present embodiment will be described with reference to the flowchart shown in FIG.

The CPU 21 of the printer body determines in step S
2, the respective temperatures Ta and Tb are obtained from the temperature sensors 46 provided on the heads 4A and 4B. In step S3, the densities OD_A and OD_B corresponding to the temperatures Ta and Tb of the heads 4A and 4B are acquired. For example, if the temperature Ta of the head 4A is AQ and the temperature Tb of the head 4B is BP, the density OD_A of the head 4A is Q and the density OD_B of the head 4B is P.

In step S4, the density OD of the head 4A
_A is compared with the density OD_B of the head 4B, and the temperature of the lower density head is set to be equal to the density of the higher density head. That is, the density OD of the head 4A
If _A is higher than the density OD_B of the head 4B (YES in step S4), a target temperature TTb of the head 4B that is equal to the density OD_A is obtained in step S5 based on the table in FIG. In the case described above, the target temperature TTb of the head 4B is BQ to be set to the density Q. On the other hand, head 4
If the density OD_A of A is not higher than the density OD_B of the head 4B (NO in step S4), a target temperature TTa of the head 4A that is equal to the density OD_B in step S6 is obtained based on the table of FIG. 8, and in step S7. finish.

In this embodiment, by controlling the temperature control heater 47, the temperature of the head can be raised to increase the density. However, since no cooling means is provided, the head having the higher density is controlled by the higher density head. The temperature of the head is controlled to match the density of the lower head. The temperature of the head may be adjusted to a target temperature lower than the actual head temperature by using a cooling device.

In the flowchart shown in FIG. 9, the set temperature is determined with reference to the density of the head at a certain temperature.
The set temperature can be determined without referring to the density of the head. This example will be described with reference to the flowchart shown in FIG.

In step S12 in FIG. 10, the CPU 21 of the printer main body acquires the respective temperatures Ta and Tb from the temperature sensors 46 provided on the heads 4A and 4B. In step S13, a provisional target temperature BA for making the head 4B equal to the density of the head 4A and a provisional target temperature AB for making the head 4A equal to the density of the head 4B are acquired. For example, the head 4A acquired in step S12
Is the temperature of the head 4B, the density of the head 4A is Q, and the density of the head 4B is P. In order to make the density of the head 4B equal to the density Q of the head 4A, the temperature of the head 4B is set to BQ according to the table shown in FIG.
Therefore, the provisional target temperature BA of the head 4B is BQ
Becomes Similarly, the provisional target temperature AB of the head 4A becomes AP.

In step S14, the tentative target temperature AB is compared with the temperature Ta of the head 4A. If the tentative target temperature AB is higher than the temperature of the head 4A, in step S5, the tentative target temperature AB for the head 4A is determined. AB is set as the target temperature TTa. On the other hand, in step S16, the provisional target temperature B
A is compared with the temperature Tb of the head B, and if the target temperature BA is higher than the temperature of the head 4B, in step S7,
The provisional target temperature BA is set as the target temperature TTb for the head 4B. In this embodiment, the temperature of the head can be raised by controlling the temperature control heater 47, but since there is no cooling means, the temperature of the head is controlled to be higher than the actual head temperature. . still,
The temperature of the head may be adjusted to a target temperature lower than the actual head temperature by using a cooling device.

If No in both steps S14 and S16, it is an error of the temperature sensor, so that step S1
In step S8, error processing is performed, and in step S19, the target temperature setting processing ends.

In order to perform the above-described target temperature setting processing,
The target temperature table shown in FIG. 8 is necessary, and a method of creating this table will be described.

FIG. 11 is a flowchart for creating a target temperature table used in the processing of FIGS. 9 and 10. In step S112, as shown in FIG.
The recording density at each temperature by a plurality of recording heads is measured in advance, and the temperature-density tables TT1 [x], TT2 [x],.
Ti [x] is created in advance. Here, TTi [x] means the density of the i-th head at the temperature x, and print data of a predetermined duty (preferably 50% or less) is supplied to the print head. It is efficient to select a head having a different density at room temperature (for example, 25 ° C.). Created temperature-
The density table is stored in the control ROM 23 of the printer main body.

In this embodiment, since the recording head is of a replaceable type, it is desirable to prepare a temperature-density table for all the recording heads that may be mounted on the printer. However, it is desirable to reduce the amount of data in the table by grouping some characteristics in order to reduce the amount of ROM.

Next, in step S113, when the head is newly mounted on the printer or when the power is turned on, the density OD of the mounted heads 4A and 4B at normal temperature is determined.
Measure a [JJ] and ODb [JJ]. The measurement of the density is performed by forming a test pattern based on the duty recording data used in step S112 and reading the test pattern by the photo sensor 31. For the concentration measured here, an absolute value or a relative value may be obtained. In the present embodiment, the absolute value is obtained in consideration of the correction system.

In steps S114 and S115, the characteristics of each head are estimated based on the measured density, and a table used for managing the target temperature is selected. In the example shown in FIG. 12, the table of the head TT2 is selected as the head 4A,
For the head 4B, the table of the head TT4 is selected. By storing the data of the selected table as the target temperature table of the heads 4A and 4B in the RAM 22, the table shown in FIG. 8 is completed.

If the relative value of the density is obtained in step S113, the table of the head TT1 is selected for the head of the lower density, and the table of the heads TT2 to TT6 is selected for the head of the higher density in accordance with the density difference. Select. When the density measured at room temperature is not equal to TTi [JJ], the table of the head with the least error may be selected or the weighted average of the tables on both sides of the measured density may be calculated.

In this embodiment, after the head is mounted on the printer, the density of the head is measured. But,
When the head is manufactured, the density of the head may be measured, the information may be held in the head, and when the head is mounted on a printer, a table may be selected based on the information. As means for holding the density information in the head, the density information may be stored directly in a ROM provided in the head, or a specific ID may be stored. Furthermore, instead of ROM,
The density information may be held by providing a specific wiring pattern or a resistor having a predetermined value on the head. After such a head is mounted on a printer, the stored data is accessed to determine the temperature-density characteristics corresponding to the head.

The target temperature table may be created by the printer itself when the head is mounted on the printer.
The head 4A records a test pattern at a temperature fixed to, for example, AO, the head 4B records a plurality of test patterns by changing the temperature, and changes the temperature of the head 4B corresponding to the same density pattern, for example, BO to AO. Make it correspond. Then, by sequentially changing the temperature of the head 4A and repeating the above steps, the target management table is completed. According to this method, even if the sensitivity of the photosensor varies from printer to printer, a target management table without errors can be created.

Next, control of the printer body during actual printing will be described with reference to the flowchart shown in FIG.

When the recording operation is started (step S2)
1) The CPU 21 of the printer body obtains the temperatures Ta and Tb of the heads 4A and 4B at a predetermined timing (step S22), and calculates the target temperatures TTa and TTb of each head based on FIG. 9 or FIG. Find (Step S2
3). Next, if the temperature Ta of the head 4A is lower than the target temperature TTa of the head 4A (YES in step S24),
The head 4A is heated (Step S25). On the other hand, the temperature Ta of the head 4A is not lower than the target temperature TTa (NO in step S24), and the temperature Tb of the head 4B is
If the temperature is lower than the target temperature TTb of B (Y in step S26)
ES), the head 4B is heated (step S27).

The above steps are repeated until the temperatures of both heads 4A and 4B become equal to or higher than target temperatures Ta and TTb, respectively, and printing is started only when these conditions are satisfied (steps S28 and S29).

In the above-described example, since the recording is started when all the heads (here, the heads 4A and 4B) reach the set temperature during the recording, the image density can be made uniform on the left and right sides of the recording area.

Another control of the printer main body at the time of actual printing will be described with reference to a flowchart shown in FIG. 14, the same steps as those in the flowchart shown in FIG. 13 are denoted by the same reference numerals. The difference between the control shown in FIG. 14 and FIG. 13 is that, after steps S35 and S37 for heating the head 4A or the head 4B, the process immediately proceeds to step S38 for recording.

That is, in this example, recording is started without waiting until all the heads reach the set temperature during recording. Therefore, compared with the case where the recording control of FIG. 13 is adopted,
Recording time can be shortened.

On the other hand, since the recording may be started before all the heads reach the set temperature, there is a concern that the image density varies on the left and right of the recording area, but there is no problem in practice for the following reasons. . In other words, if the target temperature is always set and controlled with respect to the head as in this example, it is considered that the actual head temperature and the target head temperature hardly differ from each other.

As described above, according to the present embodiment, based on the head temperature indicating the high density, the head having the low density is set so that the density of the head indicating the low density is equal to the density of the head indicating the high density. Is set, it is possible to reduce the difference in density in the divided recording areas even if the temperature of any of the heads fluctuates.

In the above embodiment, the total recording area is set to 2
And the two heads share the respective divided recording areas for recording. However, the present invention is not limited to this, and the entire recording area is divided into three or more,
The present invention can also be applied to a case where three or more heads are assigned.

FIG. 15 is a diagram showing a target temperature table when the entire recording area is divided into three and recording is performed using three heads. In this case, based on the head temperature indicating the highest density, the temperatures of the two low-density heads are set such that the densities of the other two heads indicating the low density are equal to the density of this head. I do.

In the above-described embodiment, the head temperature is obtained from the temperature sensor 46 provided on the head. However, the temperature may be obtained by a known head temperature estimating means. For example, an environmental sensor (not shown) for estimating the temperature fluctuation of the head based on the duty of the drive signal supplied to the head and detecting the estimated value and the environmental temperature provided in the printer body
The head temperature may be estimated from the environmental temperature acquired from the above. In this case, there is an advantage that it is not affected by the variation of the temperature sensor for measuring the head temperature.

In the above-described embodiment, all control is performed by the CPU 21 of the printer main body, but may be controlled by the printer driver 103 of the host computer.
In this case, the printer driver 103 has a target management table, and the printer driver 103 receives temperature information of a plurality of heads from the printer body. The printer driver 103 obtains a target temperature of any one of the heads based on the acquired temperature information in accordance with the processing shown in FIG. 9 or FIG. 10 and transmits the target temperature to the printer main body. As a result, the printer body sets the received target temperature, and FIG.
The temperature control is performed according to the processing of 4.

In particular, when the target temperature is obtained by the printer driver 103, it is desirable to employ the above-described temperature estimating means. This is because the printer driver 103 can estimate the temperature fluctuation of the head based on the print data transmitted from the printer driver 103 to the printer main body. At this time, the printer driver 103 may periodically acquire the environmental temperature from the printer body.

Further, in this embodiment, the temperature control heater 47 is used as a means for controlling the temperature, but a cooling means such as a Peltier element may be used instead. In this case, based on the head temperature indicating the low density, the temperature of the high-density head may be set so that the density of the head indicating the high density is equal to the density of the head.

[Second Embodiment] In the present embodiment, the head 4B in the first embodiment is replaced with a head that discharges light ink, and two recording heads 4A and 4B using dark and light inks having different densities are used in cooperation. Work and overlap recording area "154m
This is an example of a case where a gradation recording image is formed on m ". At this time, the recording data supplied to the heads 4A and 4B differ depending on the image, and thus the temperatures of the heads 4A and 4B may differ. Increases, the viscosity of the ink decreases, the amount of ink discharged increases, and the image density increases, so that the linearity of gradation cannot be maintained.

In FIG. 16A, the densities of the heads 4A and 4B indicated by solid lines are in a predetermined relationship (here, dark ink) by a known density correcting means, for example, a pulse signal correcting means or a head temperature correcting means. Is set to be twice the density of the light ink and 1: 2). In the drawing, cyan is represented as a representative, and the density of the light ink is shown to be equal to the density of the dark ink for convenience. On the recorded image, since both inks are superimposed, the density appears as a thick solid line.

FIG. 16B shows that the print data of the head 4A, that is, the head of the dark ink has a high duty, and the density (shown by a dashed line) of the head 4A is the initial density relationship with the head 4B (1: 2). If recording is performed in this state, the density becomes higher in the high density area (indicated by a thick wavy line).
As described above, the linearity of gradation cannot be maintained.

Therefore, as shown in FIG. 16C, it is necessary to increase the density of the head 4B as shown by a broken line to maintain the initial density relationship with the head 4A. As a result, the linearity of the gradation can be maintained (shown by a thick solid line).

(A) to (C) shown in FIG. 17 show the case where the duty of the print data of the head 4B, that is, the light ink head is increased, contrary to (A) to (C) shown in FIG. By increasing the density of the head 4A, the linearity of gradation is maintained.

The control shown in FIGS. 16 and 17 is the same as in the first embodiment. However, since the basic density differs greatly between the dark head and the light head, the target temperature table as shown in FIG. 8 cannot be directly used. In the present embodiment, since the density of the dark ink on the paper at room temperature is twice the density of the light ink, the target temperature is determined so as to maintain the initial relationship. That is, as shown in FIG. 18, the temperature-density characteristics of the dark ink head 4A and the temperature-density characteristics of the light ink head 4B are individually measured, and the density of the dark head is twice the density of the light head. Indeed, a target temperature table is created.

It is also possible to employ the table shown in FIG. In this case, the density at the acquired head temperature of the dark head, the density at the acquired head temperature of the light head,
The target temperature can be determined by comparing the corrected densities obtained by multiplying the respective corrected coefficients by a predetermined coefficient.

As described above, according to the present embodiment, based on the head temperature indicating the density higher than the predetermined relation, the density of the head indicating the density lower than the predetermined relation is determined. Since the temperature of the head whose density is lower than the predetermined relation is set so that the density is in the predetermined relation, the linearity of the gradation in the overlapping recording area is maintained even if the temperature of any of the heads changes. can do.

The present embodiment is not limited to a shuttle type printer, but can also be applied to a general serial type or full multi type density recording printer.

Further, various modifications described in the first embodiment can be applied to the present embodiment. For example, creation of a target temperature table, estimation of head temperature, and examples of control by the printer driver 103 can be applied to the present embodiment.

Third Embodiment In the first and second embodiments described above, the case where one head 4 ejects four colors of ink has been described. In this case, even if the duty of the print data is largely different for each color, the difference in the discharge amount between the colors does not become so large because the discharge ports for each color are formed on the common substrate.

In this embodiment, a case will be described in which heads for ejecting black, yellow, magenta, and cyan inks are separately mounted. The configuration of the head is basically the same as that shown in FIG. 3, but the number of heating elements 41 is 128, and ink of each color is discharged from the discharge port of each head.

In this example, in a low density area, a black image is represented by a PCBk (Process Color Black) made of three colors of yellow, magenta, and cyan instead of black ink. In the high density area, 4
A black image is represented by color.

In FIG. 19, if the heads of the black, yellow, magenta, and cyan color inks are A to D, respectively, the print data supplied to the heads A to D differs depending on the image. Different cases arise. That is, when the temperature of the head increases, the viscosity of the ink decreases, so that the amount of ejected ink increases and the image density increases. As a result, the color balance and the gray balance cannot be maintained.

In FIG. 19A, the densities of the heads A to D indicated by solid lines are set in a predetermined relationship by known density correction means, for example, a pulse signal correction means or a head temperature correction means. On the recorded image, the ink ejected from each head is superimposed, and thus appears as a PCBk density indicated by a thick solid line.

FIG. 19B shows that the duty of the print data of the head B, that is, the head of the cyan ink is high, and the density of the head B (indicated by a broken line) is different from those of the other heads A,
This indicates that the density was higher than the initial density relationship with C and D. If printing is performed in this state, the hue deviates from the expected black.

Therefore, as shown in FIG. 19C, it is necessary to maintain the initial density relationship with the head 4B by increasing the density of the heads C and D as shown by the broken lines. As a result, a hue shift can be prevented.

Here, FIG. 19B and FIG.
Although the density of PCBk is shown for reference, this embodiment focuses on maintaining hue, that is, color balance, instead of maintaining linearity of PCBk.

This relationship will be described with reference to the hue diagram shown in FIG. This figure is a hue diagram obtained by cutting out a color space at a certain black density. Originally, the CMY balance is set to be the expected black (PCBk in FIG. 20), and the relationship between the densities of the respective colors at this time is as shown in FIG. 19A. When a certain color, here, only the cyan head C, is heated as shown in FIG. 19B, the color becomes strong and the hue is shifted from the expected black, that is, FIG.
20 (Cyanic PCBk) (arrow a in FIG. 20). Therefore, the other two colors are adjusted so as to be expected black ((C) shown in FIG. 19), thereby preventing hue shift (arrow b in FIG. 20).

In this case, the density of CMY becomes higher with respect to black as a whole, and the density of PCBk becomes higher in the middle density region as shown in FIG. Therefore, P
In order to maintain the gradation of CBk, it is necessary to adjust the density of the head A of the black ink. This adjustment is the same as correcting the density of the halftone black and the density of the high density black, that is, performing the correction at the time of grayscale recording with black. This is the second
The correction is the same as the correction at the time of cyan gradation recording described in the embodiment, and the description is omitted here.

In this embodiment, when a head of a certain color is heated, the target temperatures of the other two colors are set.
The target temperature table shown in FIG. this is,
A PCBk table at room temperature is created by a conventional method, and when a certain head is set to a predetermined temperature, if the other two heads are set how many times, if these are mixed,
Check whether it becomes black, and the density 1 of １ ／ of the black density K after temperature control
K-CMY target temperature table TT using / 2 · K as a function
c [K], TTm [K] and TTy [K]. In this case, it is desirable to create the table with the CMY balance for creating 50% density black in terms of the highest correction efficiency.

When the characteristics of each color of the head are different,
It is desirable to consider the characteristics of each head, but since it is a combination with the temperature control correction of the left and right heads described in the first embodiment, the description thereof will be omitted.

The target temperature setting control of the printer main body according to the present embodiment will be described with reference to the flowchart shown in FIG.

The CPU 21 of the printer main body executes step S
At 42, the respective temperatures Tc, Tm, Ty are obtained from the temperature sensors 46 provided for the respective heads. Step S4
In No. 3, black densities K [Tc], K [Tm], K corresponding to the temperatures Tc, Tm, Ty of the respective heads using the table shown in FIG.
Get [Ty]. For example, the temperature Tc of the head C is CQ,
Assuming that the temperatures Tm and Ty of the heads M and Y are MP and YP,
Black density K [Tc], K corresponding to each of heads C, M, Y
[Tm] and K [Ty] are Q, P, and P, respectively.

In steps S44 to S46, the corresponding black densities K [Tc], K [Tm] and K [Ty] are compared, and the one having the highest density is detected. If the corresponding black density K [Tc] is the highest density, in step S47, the heads M and Y
Are set to temperatures (in this case, temperatures MQ and YQ) at which the density of the heads M and Y becomes the corresponding black density K [Tc] (in this case, density Q). Similarly, if the corresponding black density K [Ty] is the highest density, the target temperatures TTc and TTm of the heads C and M are set in step S48,
If the corresponding black density K [Tm] is the highest density, step S
At 49, the target temperatures TTc, TTy of the heads C, Y
Is set, and the process ends in step S50. The subsequent temperature control is the same as in the first embodiment, and a description thereof will be omitted.

As described above, according to the present embodiment, based on the head temperature indicating the density higher than the predetermined relationship, the head indicating the corresponding black density lower than the black density corresponding to this head is indicated. So that the concentration of
Since the temperature of the head having the corresponding black density lower than the predetermined relationship is set, the color balance in color printing can be maintained even if the temperature of any of the heads changes.

The present embodiment is not limited to a shuttle type printer, but can be applied to a general serial type or full multi type color printer.

The various modifications described in the first embodiment can also be applied to the present embodiment. For example, creation of a target temperature table, estimation of head temperature, and examples of control by the printer driver 103 can be applied to the present embodiment.

[Fourth Embodiment] In this embodiment, a case will be described in which a head for discharging black ink and a head for discharging yellow, magenta, and cyan ink are mounted separately. The structure of the head is basically the same as that shown in FIG.
The number of 1 is 128. The number of heating elements 41 of the head that ejects Y, M, and C inks is 160, which corresponds to a total of 48 for each color and 8 between each color.

In this example, a black image is represented by a PCBk (Process Color Black) made up of three colors of yellow, magenta, and cyan instead of black ink in the low density area. In the high density area, a black image is expressed by black ink and PCBk.

In the above-described third embodiment, since the color heads are independent of each other, the density change is also independent. However, in this embodiment, since the color heads are integrated,
It can be considered that they change almost in common. Therefore, in the present embodiment, the problem of gray balance is more important than the problem of color balance.

Assuming that the black ink head is A and the color ink head is B, since the heads A and B are separate bodies, the density of the black head A and the density of the color head B vary independently. Since the recording data supplied to the heads A and B differ depending on the image, the temperatures of the heads A and B may differ. That is, when the temperature of the head increases, the viscosity of the ink decreases, so that the amount of ejected ink increases and the image density increases. As a result, similarly to the third embodiment, the gray balance cannot be maintained.

In FIG. 23A, the density of the head A and the density of the head B indicated by a solid line are set in a predetermined relationship by known density correcting means, for example, a pulse signal correcting means or a head temperature correcting means. Since the inks ejected from both heads are superimposed on the recorded image, they appear as PCBk densities indicated by thick solid lines.

In FIG. 23B, the duty of the print data of the head A, that is, the head of black ink is high, and the density of the head A (indicated by a dashed line) is higher than the initial density relationship with the head B. It has become. If recording is performed in this state, the density will be further increased in the high density area (indicated by a thick wavy line), and as described above, the gray balance cannot be maintained.

Therefore, as shown in FIG. 23 (C), the density of the head B is increased as indicated by the dotted line, and the density of the head A is increased.
It is necessary to maintain the initial concentration relationship with. As a result,
The gray balance can be maintained (shown by thick wavy lines).

FIGS. 24A to 24C show cases where the duty of print data of the head B, that is, the color ink head, is high, contrary to FIGS. 23A to 23C. Is shown. As shown in FIG. 24C, the gray balance is maintained by increasing the density of the head A.

The setting of the target temperature in the present embodiment can be obtained by comparing the corrected densities, as in the above-described second embodiment. This correction density is obtained based on a predetermined relationship between the density of black ink and the density of PCBk.

As described above, according to the present embodiment, based on the head temperature indicating the density higher than the predetermined relation, the density of the head indicating the lower density than the predetermined relation is determined. Thus, the temperature of the head having a lower density than the predetermined relationship is set, so that the gray balance in color printing can be maintained even if the temperature of any of the heads changes.

The present embodiment is not limited to a shuttle type printer but can be applied to a general serial type or full multi type color printer.

Further, various modifications described in the first embodiment can also be applied to the present embodiment. For example, creation of a target temperature table, estimation of head temperature, and examples of control by the printer driver 103 can be applied to the present embodiment.

Further, the present invention is not limited to an image recording apparatus for recording binary data. The present invention is also effective in a printer that records a multivalued image, and a series of signal processing may be entirely performed by a printer driver.

The present invention can be applied not only to the ink jet recording system but also to a recording system having a recording density having a thermal characteristic, for example, the above-mentioned thermal fusion transfer recording system or thermal sublimation transfer system.

Further, the present invention relates to paper, cloth, leather, non-woven fabric, O
The present invention is applicable to all devices that use a recording medium such as HP paper or metal.

The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but it can be applied to a single device (for example, a copier, a facsimile). Device).

An object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (CPU or MP) of the system or apparatus.
It goes without saying that U) can also be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

[0131]

As described above, according to the present invention,
Even if the temperatures of the plurality of recording heads fluctuate, it is possible to prevent the quality of the recorded image from lowering.

[0132]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating density unevenness caused by a conventional multiple recording head.

FIG. 2 is a diagram for describing divided recording and duplicate recording in a recording apparatus using two recording heads.

FIG. 3 is a block diagram illustrating a configuration for driving a recording head in the recording apparatus.

FIG. 4A is a system configuration diagram showing a relationship between a recording device and a host computer.

FIG. 4B is a block diagram showing a control configuration of the printing apparatus shown in FIG. 4A.

FIG. 5 is a diagram illustrating density deviation of a plurality of heads and correction thereof.

FIG. 6 is a diagram showing temperature-density characteristics of a plurality of heads and correction thereof.

FIG. 7 is a diagram showing temperature correction of a head.

FIG. 8 is a diagram showing a target temperature table for a plurality of heads.

FIG. 9 is a flowchart illustrating a process of acquiring a target temperature in FIG. 8;

FIG. 10 is a flowchart illustrating another process for acquiring a target temperature.

FIG. 11 is a flowchart for creating a target temperature table.

FIG. 12 is a diagram illustrating a process of selecting a target temperature table from a temperature table.

FIG. 13 is a flowchart illustrating temperature control during recording.

FIG. 14 is a flowchart illustrating another temperature control during recording.

FIG. 15 is a diagram showing another target temperature table.

FIG. 16 is a diagram showing a density deviation of a density head and its correction.

FIG. 17 is a diagram showing a density deviation of a density head and its correction.

FIG. 18 is a diagram showing a target temperature table for a light and dark head.

FIG. 19 is a diagram showing a color balance deviation of a color head and its correction.

FIG. 20 is a hue diagram in which a color space is cut out at a certain black density.

FIG. 21 is a diagram showing a target temperature table for a color head.

FIG. 22 is a flowchart illustrating a process of acquiring a target temperature in FIG. 21;

FIG. 23 is a diagram showing a gray balance deviation of a color head and its correction.

FIG. 24 is a diagram illustrating a gray balance shift of a color head and its correction.

[Explanation of symbols]

 21 CPU 22 RAM 23 Control ROM 24 Print Buffer 25 Paper Monitoring Mechanism 26 Paper Feeding Mechanism 27 Carriage Position Detection Mechanism 28 Carriage Driving Mechanism 29 Recording Head Monitoring Mechanism 30 Recording Head Maintenance Mechanism 31 Photo Sensor 32 LED 33 PD 43 Decoder 44 Latch 45 Shift register 46 Temperature sensor 47 Temperature control heater 101 OS (operating system) 102 Application software 103 Printer driver 104 Controller software 105 Engine software 106 Recording head

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiromitsu Hirabayashi, California, United States 92626, Costa Mesa Redhill Avenue 3191 Canon Business Machines, Inc.

Claims (34)

[Claims] 1. A method for controlling an image forming apparatus for forming an image using a plurality of recording heads, the method comprising: acquiring temperatures of a plurality of recording heads; A target temperature of the other recording head is set so that an image formed by the head and the other recording head maintains a predetermined density relationship, and the temperature of the other recording head is adjusted to the set target temperature. A method for controlling an image forming apparatus, comprising: forming an image using the plurality of recording heads. 2. The method according to claim 1, wherein the setting is performed based on the acquired temperature of the one recording head such that an image formed by the one recording head and the other recording head maintain the same density. The method according to claim 1, wherein a target temperature of the head is set. 3. The method according to claim 1, wherein the plurality of recording heads form images using different color materials, and the setting step includes the step of: setting the one recording head and the other recording head based on the acquired temperature of the one recording head. 2. The method according to claim 1, wherein the target temperature of the other recording head is set such that an image formed by the head maintains a predetermined color balance. 4. The recording head according to claim 1, wherein the plurality of recording heads form an image using a color material different from the image using the black color material, and the setting step is based on an acquired temperature of one of the recording heads. The target temperature of the other recording head is set such that an image formed by the one recording head and the other recording head maintains a predetermined gray balance. A method for controlling an image forming apparatus. 5. The method according to claim 1, wherein the plurality of recording heads form an image using color materials having different densities, and the setting step includes the step of: setting the one recording head and the other based on the acquired temperature of the one recording head. 2. The method according to claim 1, wherein the target temperature of the other recording head is set such that an image formed by the recording head maintains a predetermined gradation balance. 6. An image forming apparatus for forming an image using a plurality of recording heads, an acquiring unit for acquiring a temperature of the plurality of recording heads, and the one recording based on the acquired temperature of the one recording head. Setting means for setting a target temperature of the other print head so that an image formed by the head and the other print head maintains a predetermined density relationship; and a temperature of the other print head set to the set target temperature. An image forming apparatus, comprising: an adjusting unit that adjusts image quality. 7. The other recording head according to claim 1, wherein the setting unit is configured to maintain the same density of an image formed by the one recording head and the other recording head based on the acquired temperature of the one recording head. The image forming apparatus according to claim 6, wherein a target temperature of the head is set. 8. The recording head according to claim 1, wherein the plurality of recording heads form an image using different color materials, and the setting unit is configured to control the one recording head and the other recording head based on the acquired temperature of the one recording head. The image forming apparatus according to claim 6, wherein a target temperature of the other recording head is set so that an image formed by the head maintains a predetermined color balance. 9. The recording head according to claim 1, wherein the plurality of recording heads form an image using a color material different from the image using the black color material, and the setting unit sets the image based on the acquired temperature of one of the recording heads. The target temperature of the other recording head is set such that an image formed by the one recording head and the other recording head maintains a predetermined gray balance. Image forming device. 10. The printing apparatus according to claim 1, wherein the plurality of printheads form an image using color materials having different densities, and the setting unit sets the one printhead and the other printhead based on the acquired temperature of one printhead. 7. The image forming apparatus according to claim 6, wherein a target temperature of the other recording head is set such that an image formed by the other recording head maintains a predetermined gradation balance. 11. The image forming apparatus according to claim 6, wherein the obtaining unit obtains temperatures of the plurality of print heads by using temperature sensors provided for each of the plurality of print heads. 12. An image forming apparatus comprising: an acquisition unit configured to acquire an environment temperature sensor provided in the image forming apparatus, an environment temperature from the environment temperature sensor, and a duty of a print signal supplied to each of the plurality of print heads. 7. The image forming apparatus according to claim 6, further comprising: estimating means for estimating a temperature of each of the plurality of recording heads. 13. The image forming apparatus according to claim 6, wherein the plurality of recording heads are arranged at a predetermined interval in a scanning direction. 14. The image forming apparatus according to claim 13, wherein the plurality of recording heads are capable of recording in the same color and recording while sharing an area in a scanning direction. 15. The other recording head according to claim 1, wherein the setting unit is configured to maintain the same density of an image formed by the one recording head and the other recording head based on the acquired temperature of the one recording head. The image forming apparatus according to claim 14, wherein a target temperature of the head is set. 16. The image according to claim 6, wherein the plurality of recording heads are capable of recording at different densities, and record a gradation image in cooperation with overlapping recording areas overlapping in the scanning direction. Forming equipment. 17. The image forming apparatus according to claim 17, wherein the setting unit is configured to maintain the predetermined gradation balance of an image formed by the one recording head and the other recording head based on the acquired temperature of the one recording head. 17. The image forming apparatus according to claim 16, wherein a target temperature of the other recording head is set. 18. The image forming apparatus according to claim 6, wherein the setting unit includes a temperature-density table indicating a density for each of the plurality of print heads. 19. The setting unit acquires densities corresponding to the acquired temperatures of a plurality of recording heads from the temperature-density table, and sets a temperature at which the acquired density becomes the highest concentration among the plurality of recording heads. 19. The image forming apparatus according to claim 18, wherein each of the plurality of recording heads is acquired from the temperature-density table, and the acquired temperature is set as a target temperature of the plurality of recording heads. 20. The image according to claim 6, wherein the setting unit includes a temperature table indicating a provisional target temperature required for each of the plurality of recording heads to maintain a predetermined density relationship. Forming equipment. 21. The setting means obtains, from the temperature table, temporary target temperatures of other print heads corresponding to the obtained temperatures of the plurality of print heads, and sets a higher temporary target temperature among the obtained temporary target temperatures. 21. The image forming apparatus according to claim 20, wherein the provisional target temperature is set as the target temperature for the recording head having the target temperature. 22. The image forming apparatus according to claim 6, wherein said adjusting means includes a heating means for heating said recording head. 23. The image forming apparatus according to claim 6, wherein the adjusting unit includes a cooling unit for cooling the recording head. 24. The image according to claim 6, wherein the forming unit forms an image using the recording head after the recording head reaches a target temperature set by the adjusting unit. Forming equipment. 25. The printer according to claim 19, wherein: before the recording head reaches a target temperature set by the adjusting unit,
The image forming apparatus according to claim 6, wherein an image is formed using the recording head. 26. The image forming apparatus according to claim 6, wherein said plurality of recording heads eject ink by heat. 27. A printer driver which is installed in a host computer and controls a printer, comprising: a code for acquiring a temperature of a plurality of recording heads mounted on the printer; and a temperature of one of the acquired recording heads. A code for setting a target temperature of the other recording head to the printer so that an image formed by the one recording head and the other recording head maintain a predetermined density relationship. Printer driver. 28. The code to be set, based on the acquired temperature of one of the printheads, such that the image formed by the one printhead and the other printhead maintain the same density. The printer driver according to claim 27, wherein a target temperature of the recording head is set. 29. The plurality of recording heads form images using different color materials, and the setting code is based on the acquired temperature of one of the recording heads and the other recording head and the other recording head. 28. The printer driver according to claim 27, wherein a target temperature of the other recording head is set so that an image formed by the head maintains a predetermined color balance. 30. The plurality of recording heads form an image using a black color material and an image using a different color material, respectively, and wherein the setting code is set to a temperature of one of the acquired recording heads. 28. The target temperature of the other recording head is set based on the target recording head such that an image formed by the one recording head and the other recording head maintains a predetermined gray balance. Printer driver. 31. The plurality of printheads form an image using color materials having different densities, respectively, and the setting code is based on the acquired temperature of one of the printheads and the other printhead and the other printhead. 28. The printer driver according to claim 27, wherein a target temperature of the other recording head is set such that an image formed by the other recording head maintains a predetermined gradation balance. 32. The printer driver according to claim 27, wherein the acquired code acquires a detected temperature from a temperature sensor provided in the plurality of recording heads. 33. The acquired code acquires a detected temperature from a temperature sensor provided in the printer, and generates the plurality of codes based on the detected temperature and a duty of a recording signal supplied to each of the plurality of recording heads. 3. The temperature of each of the recording heads is obtained.
7. The printer driver according to 7. 34. A recording medium according to claim 2, further comprising a code for supplying a recording signal to said plurality of recording heads.
7. The printer driver according to 7.